1. Field of the Invention
The present invention is directed to the field of plastic fencing.
2. Background Art
Plastic fencing has made severe inroads on traditional wooden fencing, and many miles of plastic fencing are installed each year. While there are numerous styles of fencing, one popular style consists of hollow posts which are sunk in the ground, with or without the aid of cement, or in the case of decks, mounted on special mounting bases. Spanning the gap between the posts are one or more horizontal rails. These rails may be unadorned, or vertical members may be attached to form solid fences, picket fences, etc. Numerous styles are possible.
Assembly of the fence requires the rails to be secured to the posts. For this purpose, metal brackets may be used, as disclosed in U.S. Pat. No. 5,938,184. However, this method of assembly is time consuming and results in an observable bracket which therefore fails to mimic a traditional wooden fence. Thus, more commonly, the posts are supplied with holes into which the rails pass. The holes may be manufactured into the post by the manufacturer or cut on the job site. A typical post/rail assembly is shown in FIGS. 1 and 2. In FIG. 1, a post and rail assembly is illustrated from the side. The post 1 in this case is a square post with walls 3 which may typically be about 0.25 inch thick. On faces 5 and 6, are rectangular holes 7 for receiving a fence rail 9. The rail end 10 protrudes some distance into the interior of the post. A section across 2—2 is shown in FIG. 2.
A problem with post/rail systems such as those of FIGS. 1 and 2 is that the fences exhibit a considerable amount of “wobble,” even when posts are set in concrete. The reason for this wobble has to do with a lack of rigidity due to the fact that the rails are free to move within their holes in the post, as shown in FIG. 3, the same structure as depicted in FIG. 2, but with a sidewards force imposed upon the structure. The rails, rather than being spaced 180° apart, now make an oblique angle with respect to each other. In long runs of fences, these problems are exacerbated.
In U.S. Pat. No. 5,702,090, rather than extend into the post through its sidewall, rails are captured by a recess, which also serves to hold a framing member for vertical slats. However, the recess is too shallow to cause any appreciable stiffening of the fence line. Moreover, this construction requires a more complex extruded post, one which also fails to mimic traditional wooden fencing, and requires greater accuracy during installation, as spacing is critical.
It would be desirable to provide a plastic fencing system which is economical, easy to install, and which has a much reduced tendency to wobble. Such a system would employ simple post/rail systems where the rails are inserted through holes in the post, while yet forming a robust assembly.